Abstract
Controlling the in-plane magnetocrystalline anisotropy and interfacial exchange coupling between ferromagnetic (FM) layers plays a key role in next-generation spintronic and magnetic memory devices. In this work, we explored the effect of tuning the magnetocrystalline anisotropy of La(2/3)Sr(1/3)CoO(3) (LSCO) and La(2/3)Sr(1/3)MnO(3) (LSMO) layers and the corresponding effect on interfacial exchange coupling by adjusting the thickness of the LSCO layer (t(LSCO)). The epitaxial LSCO/LSMO bilayers were grown on (110)(o)-oriented NdGaO(3) (NGO) substrates with a fixed LSMO (top layer) thickness of 6 nm and LSCO (bottom layer) thicknesses varying from 1 to 10 nm. Despite the small difference (∼0.2%) in lattice mismatch between the two in-plane directions, [001](o) and [11̅0](o), a pronounced in-plane magnetic anisotropy was observed. Soft X-ray magnetic circular dichroism hysteresis loops revealed that for t(LSCO) ≤ 4 nm, the easy axes for both LSCO and LSMO layers were along the [001](o) direction, and the LSCO layer was characterized by magnetically active Co(2+) ions that strongly coupled to the LSMO layer. No exchange bias effect was observed in the hysteresis loops. In contrast, along the [11̅0](o) direction, the LSCO and LSMO layers displayed a small difference in their coercivity values, and a small exchange bias shift was observed. As t(LSCO) increased above 4 nm, the easy axis for the LSCO layer remained along the [100](o) direction, but it gradually rotated to the [11̅0](o) direction for the LSMO layer, resulting in a large negative exchange bias shift. Therefore, we provide a way to control the magnetocrystalline anisotropy and exchange bias by tuning the interfacial exchange coupling between the two FM layers.